Not Applicable.
Not Applicable
1. Field of the Invention
Prefabricated building panels built out of wood planks and logs whose tongue and groove wood components are almost free of splits and checks and whose joints between the components are so tight that they are waterproof.
2. Description of Related Art
I made a wide search and had a Washington, D.C. professional search the records for any patents granted that would anticipate my invention. Nothing close to my invention was found and I reported none in my initial application Ser. No. 09/259,627xe2x80x94Feb. 26, 1999. However, the examiner in his first action on this application listed and discussed several previously granted patents that had teaching in the field of my invention. I am now responding on each of these inventions in respect to the examiner""s discussions. But none of this art refers to using tangential shrinkage in wood to tighten joints between wood planks.
2a. Johnson U.S. Pat. No. 4,443,990, Apr. 24, 1984. By making shrinkage relief saw slits on each side of logs and close to being in line with the heart, Johnson teaches as I have done a means to avoid almost all chances of splits or checks forming from shrinkage known as tangential shrinkage. As this is a practice widely used in the art, I made no claim for invention here. However, Johnson does not refer to tangential shrinkage being used to seal joints between other logs, in fact a second or additional logs or planks are not mentioned.
2b. Choiniere et al, U.S. Pat. No. 5,400,845, Mar. 28, 1995. The inventors here teach a fastener that ties logs together that is unique and is now used widely in the field by log home builders who, like myself, buy these special screws from the assignee of this patent. However, these screws are not used in a manner so that setting is hindered, in fact, the use of a lubricant to aid settling is taught. If the screws extended to the 80% point in the thickness of the lower logs there would be a better chance that the threads of the screws would be locked into a fixed position in the lower logs as these logs shrink from radial shrinkage. Also, if the head of the screws were set tightly to the logs above the screw heads and the screw heads were wider, settling of the logs would be hindered as these screw heads would literally xe2x80x9chang upxe2x80x9d the logs above them. Then, my main claim of tightened joints between logs from tangential shrinkage is not even addressed.
2c. Fell, U.S. Pat. No. 3,863,409, Feb. 4, 1975. Fell presents a joint sealing means that puts the weight of the log on two parallel pointed tongues extending along each side of the undersides of the logs. Also, the added weight of the logs above will tend to crush the points or crush the points into the surface of the logs below. The pointed tongues would work better, but all log houses use the weight of the log plus the weight of the logs above to seal joints between the logs. However, this does not always work, the surface of the logs are covered with knots or cut off branches. These knots or branches do not shrink lengthwise as the logs shrink radially and branches between logs pop out and actually hang the logs up creating spaces on each side of the knots through which the wind whistles into the house. My sealing system differs entirely. Elongated tongue and grooves join the tiers of logs together. Tangential shrinkage forces the tongue of the lower log and the side of the groove of the upper log tightly (almost to the point of crushing the wood) together. Because my logs are hung up on the screw heads, they do not settle, but each log individually shrinks slightly radially but not enough to pull the tongues out of the grooves so my wall remains airtight. Some of the radial shrinkage will be recovered as the logs swell more radially in wet weather, so inclement weather makes my wall airtight. My invention works on entirely different principals and is not anticipated by the Fell invention.
2d. Wrightman U.S. Pat. No. 5,020,289, Jun. 4, 1991. Here a log wall is sealed against air or water infiltration between logs using a form of weather stripping that can be compressed 50% and recover. It has secondary seals referred to as a caulk, which can stand 25% compression. This is not a wood crushing against wood seal and though it is excellent and advanced log house art, it does not anticipate my invention.
2e. Peter Sing U.S. Pat. No. 5,485,794, Jan. 23, 1996. I personally know Mr. Sing and appreciate his continuing research and development in the field of cedar joinery. Mr. Sing has developed some very good joinery art, but this patent covers mostly pallet construction that requires no seals between components. A floor is shown with no connections between the flooring pieces such as ordinary tongue and grooves that are used with most floors. Walls are illustrated, but no claims are made on walls and no reference is made to sealed joints between wall siding components. Besides his patent does not apply to sealed joints between components. I personally know Mr. Sing""s products and he does not try for sealed joints between components in his operations. This patent does not anticipate my invention.
2f. Little U.S. Pat. No. 5,887,331, Mar. 30, 1999. This is a system to tie down polymer plastic decking planks (not wood planks) to under framing using metal clips. No mention is made of sealing joints between planks and it appears that the planks are outside decking where it is preferable that rain can drain throughout the deck between the planks and not risk puddling. Plastic is free of shrinkage and warping problems and there is no way you can turn these otherwise undesirable features that wood has into useful purposes. This invention does not anticipate my invention and is dated after my patent was filed (Mar. 30, 1999 vs. Feb. 26, 1999).
2g. Hubbard U.S. Pat. No. 5,577,356, Nov. 26, 1996. Mr. John Hubbard is a neighbor and he and his buildings are well known to me. I should also mention that I know the building system covered in Mr. Hubbard""s invention. I have viewed buildings under construction and I am continuing to examine buildings that have been standing for up to three years. I have recently and also two years ago, examined his operation from a view of purchasing his company. Mr. Hubbard has conveyed to me the various points of his RandD work including this patent, which he calls his xe2x80x9cPhoenixxe2x80x9d building. The invention states that the use of an adhesive between touching surfaces is preferred. The builders I saw building these houses were not using adhesives, however, there are signs that an adhesive has been used in a finished building I viewed, but the adhesive was dry and had cracked and, in one case, it had been supplemented by a caulking, which was also drying out. Horizontal tongue and groove joints can and do leak. The joints I have seen were not tight (not so tight that the planks have to be driven together with a 5 kg. mallet as do my plank walls). Weather and resultant alternate shrinkage and swelling had opened up the joints. Most of the horizontal timbers shown in his patent drawings have rounded edges presenting an open vee to the weather. Horizontal rain driven by strong winds force water into tongue and groove joints and a siphon action sucks the water up and over the tongues and into the buildings. Water stains on the inside of the timbers in one of the buildings I viewed clearly showed the ingress of rain or melted snow.
The Phoenix building as introduced in this invention illustrates the use of laminated timbers and posts. Wood must be thoroughly kiln dried before glue lamination and it is correct to assume the wood is dry and would not be subject to the warping and cupping that is necessary for my very tight joint system to happen. Mr. Hubbard""s invention relies on an adhesive or caulking to seal out water and does not mention any help from cupping or warping to keep out rain. This invention does not anticipate my invention.
Very small logs only are used to make the tongue and groove planks so small that when the logs are sawn longitudinally into two, each half can produce a plank that either has half the heart or one has the heart and the other is very close to the heart. Each half is made into a green tongue and groove plank being machined to a tight fit between planks. The planks are immediately made into building panels and left to slowly dry out. As they dry, the wood shrinks in such a way that the joints become tighter and tighter until the wood is almost crushed within the joints which become waterproof. This invention also applies to log homes or solid timber houses whose timbers encase the heart of the log they were sawn from.
To understand this phenomenon, one needs to study wood grain and how wood shrinks when it loses water from drying. There are two kinds of shrinkage. One is between the heart and the outer rim of the log. This is called radial shrinkage. The other is along the circular growth rings around the heart. This is called tangential shrinkage. Tangential shrinkage is three or more times as great as radial shrinkage, depending on species. In the round log the wood outside of the log being exposed dries and shrinks faster than the wood near the heart of the log which is not exposed. Shrinkage means less wood on the circumference, which means it has to form splits around the log. If the round log is sawn longitudinally into two similar half logs, then it can shrink around its outer circumference without splitting. The resulting shape after drying has the line of the diameter bent out at the heart forming an obtuse angle. Tangential shrinkage is about 5% so the first 180xc2x0 line of the half green log becomes approximately a 171xc2x0 obtuse angle when the half log dries. A piece of tongue and groove lumber that is machined from the small green half log will use the flat edge of the half log as one side and will usually show the heart. When it dries, this tongue and groove plank will bend at the heart to have an angular side of up to 171xc2x0, the same as the half log. If a plurality of these green planks are attached together by edge tongue and grooves with all the hearts on one side, the combination, as they dry, will actually form a curved configuration like the side of a large wood barrel. This was the basis of my Ser. No. 09/259,627 application.
Alternatively, if a plurality of these green planks are attached together by edge tongue and grooves with the hearts being one side of the panel for the first plank and the other side of the panel for the second plank and continue with hearts alternating from one side to the other, when they dry they will form a snake-like appearance as each planks will bend in the opposite direction to its adjoining planks. This is the basis for this new application.
Either way is unsatisfactory for a flat smooth building surface, so it is necessary to nail stiff battens across the planks to keep the plurality of planks flat. Also because the thousands of narrow planks in a home would be costly to handle during construction, the manufacture of sections where enough narrow pieces are used to form a two-man load sized section makes sense. Thousands of planks become hundreds of sections and are much easier to sort out. The necessary cross battens to keep the section flat will also frame the section and provide resistance to shear forces. In order to give the section more resistance to this rack or shear force, the cross ties are let into grooves cut out across the face of the planks. The cross ties are set into the grooves tightly and nailed or screwed firmly in place. The nailing should hit the center of each plank and there should be at least four cross ties in a 8 foot high wall section. The individual planks will then be somewhat constrained from bowing and will hang on their nails. Shrinkage will occur and the tongues will need to be long enough and the grooves deep enough that the shrinkage on the edge of each plank will be about a fourth of the length of the tongues. If the plank is 2xc2xd wide the maximum shrinkage will only be about an eighth of an inch which would call for half inch long tongues. In very damp weather the planks will expand some in dry weather the planks will shrink a little in width. There will always be movement in the grooves according to humidity. Though an eighth of an inch is hardly perceptible, this movement can be disguised if the planks are grooved vertically with the shoulders of the outside tongues being set back a quarter of an inch further than the inside shoulders, forming a permanent groove between planks. If the quarter inch wide groove between planks is widened an eighth inch more by shrinkage it can hardly be noticed.
Though the individual planks are restrained from acting collectively by the cross ties, they will still bow individually, forcing the tongues to want to eschew within the tight grooves making the joint even more air tight. This would be the case if the two planks had their hearts on the same side. However, as this new application teaches if the two planks have their hearts showing on opposing sides then the cupping action will be parallel and the full surface of one side of the tongue will be forced against the full surface of one side of the groove in the next plank, whereas in the first instance only the corner of the tongue will be forced against the side of the groove. In tests my new instant configuration proved to be more airtight than the configuration of my first application (Ser. No. 09/259,627).
There are considerable economies in not kiln-drying nor air-drying the planks. Kilns represent a sizable capital investment and months of air drying costs interest on inventory investment. Then there are labor savings either way. The fact is that lower cost more air tight house sections evolve.
A greater economy is the use of only small logs (needed to include the heart or part of it on one side of every plank produced). These logs at today""s market are at the price of pulp, only a fraction of the cost of saw logs. The price of pulp logs is substantially lower than logs that are large enough to produce lumber.
Ordinarily, the handling of small logs in a sawmill is more costly than handling larger logs. Imagine passing a 4xe2x80x3 log four times past a head saw to square it. I have developed a machine that squares or shapes a log in one pass and another machine that cuts the cross notches (Four in an eight foot plank) as quick as a high powered planer can spit the planks out. A raw barked green small log freshly cut in the forest can be processed into wall, floor or roof sections within minutes and built into a nearby house within the hour.
Logs that have tops three inches or smaller (very, very small logs) cannot be made into two useful planks. However, they can be made into single planks with enough depth to be useful. Here it is necessary to saw two longitudinal shrinkage relief slits on opposite sides of the log and to a depth on each side of the log of one third of the log""s diameter and close to being in line with the log""s heart. Now the logs can dry out and shrink without splits and checks appearing on the surface. As the logs dry, the saw slits will become vee shaped when the circumference diminishes. The squares have their side slits sawn by the same machine that saws them into squares and are planed so that there are tongue and grooves cut out into their edges above and below the slits. They are then cross-grooved and battens are nailed into the cross grooves making two man-load sized sections. The upper and lower tongue and grooves will act the same way as the single tongues and grooves in the first example, they will cup outwardly away from the heart on each side of the saw slits, but there will be double the resistance to air or water passage through the doubled tongue and groove joints. In order to gain the advantage of more airtight joints every second plank will need to be split into two planks so that the split hearts can be turned outward so the section has alternate planks showing exposed hearts.
Many months of experiments have proved out this phenomenon and that it is consistent. Completely air-dried and kiln-dried sections have been examined. I found that it was impossible to separate the individual planks without breaking off the tongue or one of the sides or the groove. The planks were permanently stuck together as if they had been glued, but still can shrink or expand a little with humidity changes especially if used for open shed unheated situations. The tongues can slide a little along one side of the grooves without hurting the seal between the tongue and groove.
An even greater saving can be realized if trees are plantation grown. Various universities working with pulp and paper companies have developed very low cost wood fiber that grows 8 feet high a year and adds about one inch of new wood in diameter per year at very low cost. It is possible to grow a small log in three years or four logs in five years. As new trees will sprout from the stumps, 250 acres can produce 100 houses a year in perpetuity. The plantation can be planted close to the house factory saving in-freight costs. Using modern tree shearing equipment, the trees can be harvested like harvesting corn. The trick to make the most of this agricultural progress is to build my houses using only small, low-cost logs, which can be thinnings or the tree tops of older trees that can produce lumber sized logs, a higher and better use than pulp or firewood which is usually the fate of these small logs.
It is essential to have the cross ties across planks whether the planks (or logs) are vertical, or horizontal as in a log wall. This hangs the planks (or logs) individually on the cross ties and the possible shrinkage of each plank (or log) will not accumulate causing settlement which is the bane of the log homes made from green or undried logs. Also, as noted before, the notched-in cross ties are essential to resist shear forces. My new invention allows another method for making watertight sections where the cross ties for vertical timber walls or anti-settling ties for horizontal timber walls can be hidden internally and will keep the timbers in the same relation to each other when they individually shrink in size. Here logs are sawn in half longitudinally with the saw cut either bisecting the log""s heart or being close to it. Half the logs are planed so that they have grooves planed in each edge so that they will fit together to form panels of half logs. However, the half logs will be placed so that the heart sides and round sides will alternate from log to log from one side to the other. The double groove logs will have notches cut lengthwise on each edge of the rounded area so that hook like appendages are formed on each edge. The half logs with grooves at each edge are left rounded. A two ply section is formed by hooking the notches of a one ply section to the notches of another one ply section. The notched sides are further machined by having grooves cut across the notched faces to take cross ties, which are nailed internally as each plank is set on either side of the two ply section. This configuration as previously described sets up the opposing green half logs so that when they cup the cupping action will force the tongues of the half round planks against the side of the grooves at the flat side of the notched half round plank, making a watertight building section.
The assembly of sections using the previously described very, very small logs with 3 inch tops would be greatly improved if the small logs that are split to form alternate parts of the sections are hooked together similar to the way described in the above two ply wall or roof section.
A simpler watertight wall or roof section can be made from half logs that are machined so that each half has tongue and grooves machined into their round surfaces that are parallel to the flat surface and are cut so that if one piece of half log is flipped over its tongues will exactly fit the grooves of another half log. The round surfaces will take on a stepped pyramidal shape and are called pyramid planks. Besides being locked together by tongue and grooves the pyramid planks are held together by cross ties let into the inside face of the planks with each plank being nailed close to its center line to the rabetted-in cross ties. With four cross ties being used a two man load sized section or panel can be formed that will resist shear forces. As the individual planks are greenwood they will shrink on the cross-tie nails and the joints between the planks will open up. Water that gets in will not pass the squeezed wood part of the joints and weep grooves are cut in the top of the top tongue to drain away rain that gets into the opened joints. To hinder the sideways movement of wind driven rain towards the open joints Veed striations are cut into the top surface or exposed surface of the planks forming the sections.
If greenwood manufactured sections are stored for somtime out of the weather they will start drying out, which will askew the tongues and grooves of the planks at the edge of the section and often make them difficult to join together without splitting off tongues or a side of a groove. The best remedy for this is to have plank sized cover boards cover the joints between sections which give a pleasing board and battan appearance and also strengthens the wall or roof.
Better still, is to cut deep grooves into the edges of the cover planks, which would provide tongues that could lock into similar sized deep grooves cut into the edges of the planks at the section junction. If the exposed side of the cover plank exposes a heart then the cover plank, if green will force a much tighter locked in joint cover plank as the planks dry further. The grooves in the edge planks on each side of the section are made larger than the tongues formed in the cover plank so that it is easier to join the sections together.
There are other applications such as ceiling beams or log walls where heavy components are exposed to view on both sides where let in cross ties with nail or screw heads showing are not acceptable. Here the purpose of the cross ties can be served by the use of the long nails or screws that cross two timbers being approximately half threaded and half smooth and are spaced to give the desired resistance to shear. In the case of horizontal members accumulated shrinkage or settlement can be avoided using screws that pass down through an upper log and down through 80% of a lower log. The lower log will shrink on the screw threads and maintain their respective relationships, but the crack between the logs will widen slightly. However, the two logs won""t settle because they will be held up in place by the heads of screws fastening the two logs below them together. Such screws can take 1700 pounds of weight before the wood on the side of the screw threads is stripped and the point of the screw is forced deeper into the 20% of the lower log remaining. Second floor platforms, partitions and walls are supported by posts and beams along with the roof. The weight on the screw heads in a upper wall is negligible and the spacing of the screws for shear will govern though each building will need to have engineering calculations made to confirm the spacing of the screws particularly in the lower quarter of the log walls of each floor. In the case of the use of horizontal components that are attached to stud walls the studs will carry the weight of the floors, walls of second and third stories and roofs above.
Larger logs for log houses, or large timbers with encased hearts, will not adapt to sectionalizing because of weight. Here it will be necessary to peel the logs and cut the side shrinkage relief slits into them before storing under conditions where they will dry and shrink. Shrinkage will cause the slits to open up V-like. The logs will be easier to assemble if planing the tongue and grooves into the logs or timbers is delayed until the logs are about to be delivered to the building site. As logs take many months to dry out thoroughly they will continue to dry and shrink after the log house is built, skewing the tongue and grooves into tighter fits. Even if they are fully dried out when constructed into a log house they will pick up moisture from the air and expand skewing the tongue and grooves in a reverse way for tighter joints. We win either way. To take advantage of my more waterproof wall system, every second timber in the wall will be split close to the heart (the same as the shrinkage relief slits and the split 3xe2x80x3 small timbers previously referred to). The half timbers will be set in the wall so the half hearts are exposed on each side of the wall.